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. 2 Sheets-Sheet 2.. IE.` S. CURTIS.

Grain Mill. No. 477. Patented Nov. 23, 1837.

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ELIJAH: S.y CURTIS.. or Bosr'on, MASSACHUSETTS.

CONSTRCTION QE MILLS.

Specification. of Letters Patent No. 477'., dat-ed N'ovember 28, 1837.

To czZZ'wiom it may concern Be it known that I, E'LiJAI'i S. CUR'TS, of the city of Boston, in the county of Suifolk and' State of Massachusetts, hare invented and made a new and useful `Improvement in the Construction of Mills for the Grind'- ing of Corn, Grain, and All Such Sub-l stances asv are Usually Ground' by' al Grist or Such like Mill-which improvement is described andl speci-lied as follows-that is yto say, the drawings hereto anneXed are intended to vrepresent the various 'parts ofA a mill constructed uponl my improvedplan and are to be taken and considered 1s-apart" of this. my specification, kFigure 1 being a perspectiveview and Fig. 2 a vertical' sec tion thereofv through its center.v

The stones, or grinders are to bemade of any suitable materialofwhich stones', or grinders in. grist mills are commonly made; but I prefer the French buristone for this purpose. These stones,l or grinders may be of any such size as may' be required;

those in the mill from which theanneXedf drawings were taken are twenty inches 'in diameter andl nine inchesin thickness`andl the dimensions of the different parte of 'the mill, which I here describe, are adapted to stones, or grinders of this siZe and must be varied at the discretion of the niillv'right for stones or grinders of larger or smaller dimensions. I l

The lower stone, or grinder is designated on the drawingshereunto annexed' by the letter a, and is. mounted on a casting or frame, commonly of cast iron, which I usually make in one piece; this frame isv designated by the letter A, and forms the foundation for the mill'. In this frame is screwed a step for the spindle, designated by the letter b, an upper screw collar, designated by the letter c, and a lower screw collar, des-` ignated by the letter d. This step, and these collars, which are each separate pieces, have screws cut upon the outer sides of them, whereby they may be screwed into and out of the frame, in which there are corresponding female screws; and they may, therefore, be raised or lowered, as. may be required, at pleasure, for the purposes hereinafter mentioned. The female screws in the frame are formed most. conveniently by placing the collars. and step. in their proper places in the mold, covered with a thin coat of clay, or other suitable materiahat the time of casting the frame, and allowing the above metal tlo run around them. The step, upon which the shaft turns, for a mill of the mentioned dimensions, should be `about siX inches long and two inches in grinders in grinding different kinds of grain .and othersubstances, and.- tolower and ad- Vijus't; the upper stones, or grinders as they l wear away.

The spindle, or shaft is designated by the letter e, may be made of malleable cast `firon, jand.- stands on the step before meniti'oned and extends upward through the two `screw collars, the pulley that drives it, the f A. lower and upper grinder, and the neck ofthe hopper.

Upon the lower end of the shaft is screwed a rin-g,l or collar cl, by ,means of astrong screw the head ywhereof Eris designated by the letter m., This lower lend ofthe spindle, or shaft, however, may be made; solid, without any screw, by making a neck in the shaft and makingy the ring, or collar df in two parts; thisv latter method I prefer.

The pulley which .drives the mill is conneeted with the' shaft by means of a clutch Saud set screw, designated by the letter j, and may be disengaged at pleasure so as to g become a loose pulley.V The upper vstone grinder, near,V and a little below, the center, i is. firmly attached to, and balanced upon the shaft, by means of what I have 'denominated a rinder, designated by the. letter i,

which rinder passes through the center of the shaft, at right angles, having a ball on and being a part of it, in the center, desig.-`

nated by the letter lo, to which ball a corre'- spondingV cavity in 'the' shaft Vmakes the socket. This-ball and lsocket joint may be.

made by casting the shaft around the ball upon the rinder, protecting the parts of the rinder, wherel liberty toL move is required,`

from the approach ofthe 'metal by means of an iron tube, or other suitable appendage iitted to the rinder, or by a coat of' clay covl ering the same for the time being, and to be removed after the spindle, or shaft has been cast. It may, however, be made in any other convenient way as will be obvious to the millwright. In each end of the rinder which projects into and moves the upperV stone, in which there are suitable grooves cut to receive their ends, z', t', is inserted a screw, which comes down from the top of the stone, their heads resting upon a strong iron ring, let into'the stone, as shown at 0, 0, in the sectional drawing. The screws are designated by the letters Z, Z.

Between the heads or ends z', z', of the rinder and the ring, in the grooves cut in the stone are inserted pieces of wood m, m, or any other suitable material to support the stone. TheseV pieces can be shortened so as to lower the stone to correspond with the wear. The ring on the upper part of the stone is fastened thereto by inserting in the stone a dovetailed projection'o, 02, from the under side of the ring, around which I cast lead to keep it firm. By means of the rinder and ball and socket joint the upper stone or grinder is held firmly and at the same time, while it is balanced upon thev shaft, it is allowed a motion in every required direction, but cannot move directly up or down without vacorresponding motion of the shaft, to which it is thus attached. The upper stone, or grinder may, instead ofusing the rinders with its ball and socket joint, be Vbalanced in the like manner as the mariners compass is balanced by means of a gimbal, or universal joint. Upon the shaft, just under the valve which feeds the mill to be presently described, is Xed a cap or collar, spreading out and forming a flat table, or disk, on its upper side; this cap or collar or platform is designated by the letter n; it is movable up and down upon the shaft to regulate the distance between it and the valve (to be presently described) as may be required according to the size and quantity of the substances intended to pass into the mill. The design of this table or disk is to arrest the corn or other substance tobe ground in its passage and t0 prevent its passing into the mill except when it is in motion, when the corn orother substance will be driven from its lodgment by the centrifugal force, and scattered and set into the mill. On the upper end of the shaft is secured a small arm, or arms, leaf, or leaves, designated by the `letter o, which, when in motion, stirs the corn or other substance to be ground, acting as a shaker, and preventing its clogging in the valve. Y

The hopper is designated by the letter B,

and is, in preference, made f of cast iron.A -The neck of it is designated by the letter 1^,

and the valve for regulating the quantity admitted, by the letter 19.V The upper part of the hopper is cylindrical, lower part of its interior funnel shaped. The valve by which the feeding -is to be regulated is opened and closed, more or less, as may be required to admit more or less of the substance to be ground into the mill, by means of two horizontal screw rods, or slides, designated by the letter g, which rods come through the curb, and are there adjusted by the hand. The manner of constructing these valves is shown separately in Fig. 3. The curb is made of sheet iron and is designated by the letter o. A hoop D with a spout to allow egress to the ground material, is placed on the outside of the upper edge of the lower stone, andV is supported by movable brackets, a2, a2, attached to the stone. The upper side of this hoop is level with the surface of the lower stone, having a rim on its outer edge, within which the curb supporting the hopper is placed or fitted. The

vhopper B, which has ribs to strengthen it on the lower side of its bottom, designated by the letters r, r, these being notches at s, s, where they rest upon the curb. The curb, and the hopper which rests upon the hoop` D, are supported by brackets designated by thelletters a2,`screwed to an iron hoop 02, on the lower grinder, by screws passing through a slot, allowing them to be raised or lowered. The interior of the curb is'two inches larger in diameter than the grinders, so as to leave aspace of one inch around them, in Vmills of the above dimensions. This space may be greater or less as Vthe mill shall be larger or smaller.

The hoop D, is filled with a wooden lining designated by the letter n, in the sectional drawing, it is one inch thick and two inches in width so as to fill, completely, this space, and be tight vagainst the lower grinder. The mealpis taken from the hoop by means of the spout V, open in front, about six inches wide at the top, and three at the bottom, and is nearly perpendicular to the stones or grinders.

Between the lower screw collar (Z, which is screwed into the frame,.and the step b, is a spiral or other spring, designated by the letter 7, through which the shaft passes, bearing at its upperV end against the lower collar a, aforesaid and at the lower end upon the ring or collar, d which isV in two parts or is otherwise fitted into a neck, or groove upon the lower end of the shaft. The obj ect whereof is to keep the upper stone, or grinder at whatever `distance from the lower grinder the miller may choose to have it, and at the same time to cause it to act upon the corn, or other substance to be ground, with a regulated elastic power, or force, proportioned to the resistance to be overcome when the motion is faster, or slower, or the mill is fed with a greater or less quantity than usual, in a given time. Whenever an unsubstance so introduced to pass'out without injury 0r impediment r`to the mill, or its operations.

The actionofthe 'spring may be increased or diminished as required, by raising or lowering the lower screw collar rl, lin the frame, `and the exact degree of Velastic force required maybe thus obtained; and the `mil-ly may therefore be run with the smallest power required.

From t-he manner in which the spiral, or other spring, or 4weighted lever, is made to operate no additional friction iscaused 'on the step or on the lower end of the spindle, during the running of the stone, excepting when it tends to rise, the tension, of the spring being exerted between the lower collar (Z, which screws into the frame and the ring or collar cl', confined in the neck or groove on the spindle with its lower side resting on the upper edge of the step, which thus frees it from all friction in the neck or groove which retains it in place, until the rise of the stone raises it from this bearing. The same may be said of a weighted lever, or of any other pressure made upo-n the collar cl. The spring may be loosened or tightened, as will be obvious to the millwright, by various other methods, but t-he above mode is deemed best. Instead of the spiral,

or other spring, or springs, bearing upon the ring or collar cl, there may be a weighted lever made to act upon it and to perform the same office; but this would be less co-mpact and convenient than the spiral-spring, which I therefore prefer. The upper screw collar c, screwed in the frame has a iianch bearing on the lower grinder, or stone, so that this stone or grinder may be screwed down firmly in its place, where it is prevented from turning by means of ribs e2 in the casting. The casting or frame A, A, for the mill is usually so shaped that it will slide on the frame or floor D2, to tighten the band B2, and save the inconvenience of a friction pulley, and loss of power. The casting may be fastened to the floor or frame by means of iron dogs y, y. The step has attached to it a cog wheel D3, furnished with small teeth, and governed by a catch, Z, to enable the miller to raise and lower the upper grinder, at pleasure, and to retain the step in its place. Vhen it is required to stop the mill while the machinery that drives it is in motion, one turn of the wheel will raise the shaft and disconnect the clutch, and set screw, whereby the driving pulley is confined, and enables this pulley to move without turning the mill. This pulley is best fma'de'of cast iron, andisdesignatediby the I'letter f. llrrpullely fiXedto'the 'shaftmay'be fused instead of a'loose pulley, buttheclutch 'and set screw or1 other=contrivance for changing yit to a fast, o-r V'loose pulley, Ais 'deemed best.

curb, and hopper are described as made of "iron, yet, 'as 4will be 4obvious tothe mill- 'wright this is not essential, as lbe made of any other hard metal, or of Y wood;'but iron or hard metal is preferable.4 It will alsobe ob-vious to the millwright, ,that the above described' method of regulating the feedingof the mill, is not essential f to Ithe useof the other improvements above mentioned, as the mill may be fed in either `of the ordinary ways now in use, if the they may miller Yshall prefer it, and the (particular kind of frame above described is not Iessential -to the useo-f `the other improvements above mentioned, although it is deemed better than the method'of supporting the lower stone or grinder now in general use. For grinding large quantities of 'any` substance,

Although KJthe frame, collars, step, shaft,

where there is sufficient power, a much larger mill than that above described will be preferable; and for grinding small quantities where but little power is required a much smaller mill will be convenient; and such small mill may be turned by hand by making use kof beveled, or other cog wheels, and a winch, or crank, instead of a pulley and such mill will be very useful to families for grinding such substances as they may have occasion to grind for family use.

I will here observe that although the runner, or upper stone, in my mill will be effectually held down by the spring, or springs, or a weighted lever, and collar, which I have described, it is still a point of importance to give that weight to the runner which shall suiiice to keep it from rising under ordinary circumstances, and at its proper speed.

What I claim as new, and as of my own invention, in the above described mach-ine is:

1. The manner of balancing t-he upper stone, or runner, or grinder,and of connecting it to the spindle, or shaft, by which it is turned, by means of what I have denominated a rinder, consisting of a ball and socket, with its appendages, constructed and arranged substantially in the way described, so that said stone, or grinder, shall move freely in every required direction, as a runner ordinarily does upon a balance rynd, while it cannot rise without a corresponding motion of the spindle. And it is to be further understood that I claim, under :this head, the balancing of the stone by vmeans of a gimbal, or universaljoint, in the manner of the mariners compass, or any modifications thereof, substantially the same in principle and results.

2. I claim the manner of arranging the collars and the spiral or other spring or a Weighted lever, upon the lower end of the spindle or shaft, for retaining the runner in its place, and yet allowing it to rise when from the introduction of hard substances, or other causes, it is desirable that it should do so. Y

3. I claim the manner of constructing the step as herein described, so as to screw up or down in the frame, thus answering all the purposes of a bridge tree, and adapting itself to the spindle as the stones wear, and t-he whole superstructure descends.

4L. I claim the manner of construct-ing the valve, and the otherV parts of the feeding apparatus, including the cap, or platform on Jthe upper end of the spindle, the whole operat-ing together in the manner and for the purposesset forth.

5. I claim the manner of constructing and arranging the step, which supports the spindie, with its screw, allow it thereby to be raised or lowered, so as t-o answer all the purposes of a bridge tree, and adapting it particularly to the kind of mill above described.

6. I claim the manner of constructing and connecting the hopper curb and hoop, and the brackets by which they are sustained, in combination, as above described.

'7. I claim the general arrangement and combination of the respective parts of this mill, as herein described, and for t-he purposes set forth, whether the whole, orY only apart of my said improvements are so connected and combined.

ELIJAH S. CURTIS.

Witnesses:

W. THOMPSON, LIN'roN THORN. 

